While hair coloring becomes more popular in the consumer market, satisfactory coloring is difficult to achieve. For that reason, some users of coloring products prefer semi-permanent hair coloring instead of permanent hair coloring products. One benefit of semi-permanent over permanent hair coloring products is that semi-permanent coloring (which usually utilizes nitro dyes, azo dyes, anthroquinone dyes, etc.) can be removed by shampooing the hair 6-8 times. Sometimes, a user would want to remove the semi-permanent coloring sooner than the number of shampoos required because of an unsatisfactory or the undesirable resultant hair color. At present, no convenient and efficient method of, and product for, removing semi-permanent coloring from hair is available or known.
It is commonly known that natural hair color can be stripped and bleached with peroxide-based compositions. Such products, however, damage hair and fail to strip or bleach semi-permanent coloring from treated hair.
In DE 2,024,799, it is taught to use an aqueous mixture of alcohol and inorganic salt to remove type D and C dyes from hair. That method, however, also fails to remove semi-permanent coloring from hair.
A mixture of a sulfite, an alcohol and a cationic surfactant is disclosed in JP 4-356413 for removing color from hair at a pH of 7.0 to 9.0. Although that composition is slightly superior to the composition disclosed in DE 2,024,799 in terms of removing semi-permanent coloring from hair, its performance is still unsatisfactory.
Stripping and bleaching compositions containing a reducing agent and a chelating agent for skin are disclosed and claimed in JP 49-081548. That patent teaches the use of reducing agents, such as thioglycolic acid and its salts, at a pH of 5-9 to remove stains from skin. Such stains occurred during the coloring process. That composition does not efficiently or effectively remove semi-permanent coloring from hair as demonstrated by the examples herein below.
As a result, there exists a long-felt need for a new bleaching or stripping solution that overcomes such inefficiencies. There also exists a need for a bleaching product that can be used in the professional salon trade market and for home use via the consumer market.
The present invention overcomes these and other disadvantages of prior hair bleaching and stripping products. One object of the invention is the superior removal of more colorant and dye from hair colored with semi-permanent dyes. As a result, the user can achieve satisfactory coloring with less trial-and-error and in less time.